With the optical technology available today, there are already many optical apparatus for converting pulsed laser beams into dual pulsed laser beams. Basically, the optical apparatuses are designed to transform one pulsed laser beam into two pulsed laser beams with perpendicular polarization directions, which are together to be referred as a dual pulsed laser beam.
It is noted that dual pulsed laser beams can be used for material processing. For instance, in material surface treatment, it is used for forming anti-reflection micro/nano structures with stain resistance ability on the surface of a material by projecting the dual pulsed laser beams on the material. Moreover, when the dual pulsed laser beams are used for material ablation, not only the material removal efficiency can be improved, but also the amount of heat being generated during the ablation process can be greatly reduced.
The aforesaid optical apparatuses usually are composed of many kinds of optical elements, including splitter, reflective mirror, polarizer, half-wave plate, and so on. Operationally, when a pulsed laser beam is projected into the optical apparatus, it will first be split by the splitter and then the resulted split beams are adjusted in polarization by the use of polarizers and half-wave plates embedded in the optical apparatus, so that a dual pulsed laser beam with perpendicular polarization directions is generated.